Steel studs of a wide variety have been proposed for erecting structures.
Usually such studs are used to replace wooden studs. Wood is a relatively poor heat transfer medium. Heat losses through wooden studs has not been a significant problem in the past. Metal studs having solid webs however, do create a heat loss transfer path through the wall or other structure. This results in cold patches along the lines of the studs. Condensation, known as “ghosting” appears along these lines.
Such studs usually were formed as a C-section, i.e. there was a central web, and the opposite side edges of the web were formed into edge flanges. Several such bends were sometime incorporated in an effort to get greater strength, while using thinner gauge metal. However this did not overcome the heat transfer problem. Accordingly metal studs have been proposed with reduced heat transfer properties. These studs were formed with generally triangular or trapezoidal openings, in the web, while the two edges were formed with bends, as before. These openings were positioned so as to define diagonal struts extending across the studs. Heat losses were thus reduced since there was less metal through which the heat could pass. Also the heat transfer path was somewhat extended due to the diagonal placement of the struts. However when these studs are erected, it is usual for the builder to run services through the studs, within the wall. Where the openings in the metal studs are of these specialized generally triangular or trapezoidal shapes, the services, in many cases conduits of substantial diameter, must be able to fit through the openings.
It is not possible to the builder to cut away any of the diagonal struts to provide larger openings for services, since this would drastically reduce the strength of the studs.
The shape of these openings tended to restrict the size of the conduits which could be passed through the studs.
Another problem arose in that the triangular openings were formed with edge flanges around their perimeter. Where these edge flanges extended around an angular corner of the opening there was a tendency for the sheet metal to crack.
Consequently the corners had to be radiussed or rounded out. This meant that there was more metal at each of the corners, than was desirable for heat transfer, and thermal losses could occur.
Another problem arose in cutting these studs to length. The openings were arranged in pairs with one triangle facing one way and the next facing the opposite way. Cutting such studs to length requires that all of the openings of a particular orientation, in all of the adjacent studs in a wall frame, shall line up.
This required to facilitate passing of services through the studs. However due to the alternating orientation of the openings, this requirement resulted in cutting off end portions of studs equal in length to the space occupied by two of the stud openings, in many cases.
Concrete panels are also in wide use for attachment to the exterior of structures to provide for a wide variety of functional and aesthetic effects. Concrete panels are usually of relatively heavy thick material of great weight. Great costs are involved in both materials, labor transportation, and erection of such heavy panels. Attachment of such massive panels to the exterior of a structure also presents serious problems. Proposals have been made for using panels of reduced thickness. Such panels are reinforced by a framework of metal studs.
Usually the metal studs are partially embedded in the concrete. They provide great strength to the panels, and also facilitate erection and attachment of the panels to the structure. Usually the inside surfaces of the resulting walls are covered in with wall sheeting, typically plaster wallboard. The sheeting is often attached directly to the metal studs. The space between the concrete panels and the inner sheeting is usually insulated with suitable batts or the like. However it is known that the metal studs provide a heat transfer path which conducts heat from the building interior to the concrete panels on the exterior, and there are thus substantial heat losses through the panels due to such metal studs.
Accordingly it has been proposed to use the studs with openings described above, with reduced heat transfer properties.
It has now been surprisingly found that the use of the specialized triangular or trapezoidal shapes of these stud openings, is unnecessary.
Heat transfer reduction is possible, by the use of the invention, using openings having linear sides and with linear channel formations along at least one linear side of the openings. These linear channel formations are formed with at least two linear bends at respective first and second angles with respect to the plane of the stud, thus forming linear reinforcing channels along the sides of the openings.
A portion of the opening may be defined by a semi-circular radius. The remainder of the opening can be defined by an extended linear edge. In other embodiments the openings can be shaped with four sides, as a quadrilateral.
This means that the size of the conduit passed through the openings can be increased. The openings substantially span the distance across the web, between the edge flanges of the stud. By the use of the invention it is now possible to form openings which can accept conduits having a diameter almost equal to the distance across the web, between the edge flanges of the stud.
This is a great improvement over the earlier triangular opening configuration.
Previously this was not thought to be possible since openings with radiussed corners were thought to leave excessive metal in the stud which would cause heat transfer losses. Similar advantages can also be obtained in studs having openings of a quadrilateral shape. In both of these studs the openings are larger, and the struts running diagonally between the openings are at a greater angle, and being spaced further apart, than in studs previously known.
It has been found that by the use of relatively small additional depressions and depression openings, near each end of the diagonal struts, the actual heat transfer path can be so reduced, at critical points in the stud, so as to substantially improve on the heat transfer reduction achieved by the use of the specialized triangular or trapezoidal openings and diagonal struts of earlier studs, while at the same time increasing the strength of the stud.
Semi-arcuate openings avoid the problems caused by the corners of the triangular or trapezoidal openings and splitting of metal, and results in a much stronger stud. The use of semi-arcuate openings greatly facilitates high speed manufacture of such studs, since cutting to length becomes less critical, and there is less stud length lost in the process. The use of such openings having linear sides and with linear channel formations along at least one linear side of the openings, which are formed with at least two linear bends at respective first and second angles with respect to the plane of the stud, thus forming linear reinforcing channels along the sides of the openings, provides much increaseed strength.
The same is linear channels are also used in studs having larger quadrilateral shaped openings. This leads to further economies.
In both of these embodiments of studs the openings define service pathways for cylindrical service conduits. In each stud the conduit diameter can be almost equivalent to the distance across the stud between one side edge of the opening and the other, transversely across the stud. This means that the conduits can pass through any opening in the stud, regardless of the orientation of the opening in the stud. This greatly reduces wastage of sheet metal during manufacture.
Much larger conduits can be accepted.
Another factor in earlier designs was the thought that it was essential to remove as much metal as possible, in order to reduce heat transfer problems.
It has now been found that this was incorrect. What is required is to leave a heat transfer path which is longer than a simple transverse line directly across the stud, and which has metal removed at selected locations so as to limit heat transfer.
It has also now been found that the linear edge of each web opening can be greatly strengthened by having web openings with linear sides and with linear channel formations along at least one linear side of the openings, which channels are formed with at least two linear bends at respective first and second angles with respect to the plane of the stud, thus forming linear reinforcing channels along the sides of the openings.
This results in removing less sheet metal at each opening, rather than more This surprising development results in leaving an additional piece of sheet metal along side the linear edge. This additional piece can then be formed, in accordance with another aspect of the invention, into two generally angular bends, resulting in an additional linear channel structures within the stud. This greatly increases the strength of the stud in the critical area of the extended linear edge. The fact that more metal remains in the stud does not increase the heat transfer problems. The extra metal is in a location alongside the web opening and in this location heat cannot be passed across the stud, due to the web opening.
The blanks of sheet metal removed in this process, may be of smaller size than was the case in the blanks of metal removed for previous triangular stud openings, notwithstanding that the web openings themselves are larger. This leads to economies in the process since the blanks are smaller. Slug ejection problems in the manufacturing machinery are reduced and there is less wastage of metal.
The semi-arcuate, or quadrilateral openings reduce the problems for the builder who wishes to pass service conduits through the studs within the wall. Much larger diameter pipes can now be fed through the studs, than was possible before. This leads to less sales resistance due to a greater acceptance of the product in the market place.
These features can be used in studs having edge formations for embedment in concrete.
The features can also be used in forming much heavier duty studs with the edge formations formed into a triangular tube shape.
Even stronger heavy duty studs can be formed by severing a single strip of sheet metal along a zig-zag parting line, so as to form two separate strips of sheet metal. These two strips can be formed with formations described above and can then be joined together into a single composite structural member.
One such a composite fabrication system is disclosed in U.S. Pat. No. 5,207,045, inventor E R Bodnar, and in U.S. Pat. No. 5,592,848, inventor E R Bodnar.
However the composite members shown in those patents were difficult to fabricate, and their design shows what now appears to be structural weaknesses at critical points, which would have reduced their load bearing capacity. Such members were never in fact made, or used.
It will be appreciated that a stud which improves on all these problems associated with prior studs, will have application in general use, for many various construction applications. In particular however it will have advantages in the reinforcement of thin-shell concrete panels.